CNN  —  What an absolute roller coaster ride. OpenAI, the ChatGPT maker that has been in management upheaval for more than four months, announced that its co-founder and CEO Sam Altman would return to its board of directors as part of a reshaped oversight team. Altman in November was fired as CEO and director by the OpenAI board in a shocking dismissal of an executive who had become the face of AI in Silicon Valley. But in an equally surprising turn of events, Altman was rehired weeks later. At one point, OpenAI had three CEOs in the span of three days. Since then, OpenAI has been in recovery mode, and its $13 billion partnership with Microsoft has grown even closer – Altman had worked for about a week at Microsoft after his ouster and before his return to OpenAI. That relationship has tightened Microsoft’s grip on the world’s most important emerging technology and given it sway over the company behind AI’s most impressive and famous consumer product. OpenAI’s leadership, meanwhile, has been in flux. The company, after Altman’s return, fired the directors responsible for his ouster and hired economist Larry Summers, the former Obama and Clinton official, as well as Salesforce co-CEO Bret Taylor as chair. The only existing board member OpenAI had kept was Quora CEO Adam D’Angelo. On Friday, OpenAI announced the appointment of four new directors: Altman, former Gates Foundation CEO Sue Desmond-Hellman, former Sony General Counsel Nicole Seligman, and Instacart CEO Fidji Simo. “I am excited to welcome Sue, Nicole, and Fidji to the OpenAI Board of Directors,” Taylor said in a statement. “Their experience and leadership will enable the Board to oversee OpenAI’s growth, and to ensure that we pursue OpenAI’s mission of ensuring artificial general intelligence benefits all of humanity.” OpenAI also announced the completion of an independent investigation into the circumstances surrounding Altman’s firing. The probe, conducted by law firm WilmerHale, concluded that Altman was fired for exactly the reason the board stated: a breakdown of trust between Altman and the board – not any concern for safety or security related to artificial intelligence, as some have speculated.